Multiple foam energy absorbing substrate assembly

ABSTRACT

The present invention relates to a multiple foam substrate of predetermined shape and a method of manufacturing the substrate. The substrate is a multiple foam substrate which may be manufactured by the method with a mold having first and second mold cavities. The method includes injecting a first foam into the first mold cavity sufficiently to fill the first mold cavity and storing the first foam in the first mold cavity for a predetermined time sufficient to form a substantially non-mixing surface on the first foam. The method further includes injecting a second foam into the second mold cavity and onto the non-mixing surface on the first foam sufficiently to fill the second mold cavity. The method further includes storing the second foam in the second mold cavity for a predetermined time sufficient to bond the first foam to the second foam along the non-mixing surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a division of U.S. application Ser. No.09/561,002 filed Apr. 28, 2000.

TECHNICAL FIELD

[0002] The present invention relates to a multiple foam substrate forimpact energy absorption and airbag deployment, and a method of makingthe same in vehicles.

BACKGROUND ART

[0003] There is a growing need to improve the impact energy absorptionproperties of automotive interior trim substrates. Such sheet metalstructures include pillars, side rails, and roof structures. However,the industry has been challenged in determining a cost effective way ofmanufacturing interior trim substrates and interior components in orderto meet industry demands. For example, manufacturers continue to searchfor ways of improving the properties of substrates for absorbing energyin a cost saving manner while providing structural support.

[0004] One challenge that manufacturers are faced with is that impactenergy absorption throughout the passenger compartment, such as onpillars, side rails, or the roof structure of a vehicle, requiresdifferent energy absorption material, including molded foam or beads.This is due to the vehicle structure design which typically includes aplurality of sheet metal pieces that form the passenger compartment of avehicle. The thickness and geometric stiffness of the sheet metaltypically determine the amount of energy absorption material required.That is, the thicker and/or stiffer the sheet metals is, the moreabsorption material is required to meet industry demands. Thus,different energy absorption materials would be useful to have ininterior trim substrates.

[0005] There is also a growing need to improve airbag deploymentproperties of automotive interior trim substrates. Upon impact, airbagsmay be deployed from various locations within a vehicle compartment,such as pillars, side panels, roof structures, and front panels.However, the industry has also been challenged in determining a costeffective way of manufacturing interior trim substrates with airbags andinterior components in order to meet industry demands. For example,manufacturers continue to search for ways of improving the properties ofa substrate for accommodating an airbag disposed thereto to deploy fromthe substrate.

[0006] A deployable airbag is typically disposed between the metal sheetstructure, such as a pillar, and the interior trim substrate. The airbagis typically fastened to an area of the sheet metal structure andadjacent the energy absorbing part which is covered by an interiorsubstrate. This separate manufacturing and assembly process used indisposing the deployable airbag between the structure and the interiortrim substrate results in further additional manufacturing time andcosts.

[0007] Although current energy absorbing parts are adequate,improvements can be made thereupon. Currently, multi-component parts aremanufactured for impact energy absorption and air bag deploymentpurposes. Some multi-components are separately manufactured and thencombined to comprise a part which is fastened to an area of a vehiclecompartment, such as a pillar. More particularly, a single foam ismolded to form a shape of a vehicle component to which it may beattached. The molded foam is then adhered to a predetermined area on aninterior trim material or a shell which then fastens onto the structureof a vehicle. The separate manufacturing processes used in forming themolded foam and the interior trim substrates result in additionalmanufacturing time and costs.

[0008] Thus, what is needed is an improved system and method of makingan integrally formed substrate that more efficiently meets the industrydemands for energy absorption on collision impacts.

[0009] What is also needed is an improved system and method of making asubstrate that provides for a deployable airbag system for deploymenttherefrom.

DISCLOSURE OF INVENTION

[0010] An object of the present invention is to provide for a method ofmanufacturing a multiple foam substrate of a predetermined shape forselective impact energy absorption with a mold having first and secondmold cavities. The method includes injecting a first foam into the firstmold cavity sufficiently to fill the first mold cavity, and storing thefirst foam in the first mold cavity for a predetermined time sufficientto form a substantially non-mixing surface on the first foam. The methodfurther includes injecting a second foam into the second mold cavity andonto the non-mixing surface on the first foam sufficiently to fill thesecond mold cavity, and storing the second foam in the second moldcavity for a predetermined time sufficient to bond the first foam to thesecond foam along the non-mixing surface, whereby to define the multiplefoam substrate having the predetermined shape.

[0011] Another object of the present invention is to provide for amethod of manufacturing a multiple foam substrate of a predeterminedshape for selective impact energy absorption and airbag deployment witha mold having first and second cavities. The method includes injecting afirst foam into the first mold cavity sufficiently to fill the firstmold cavity, and storing the first foam in the first mold cavity for apredetermined time sufficient to form a substantially non-mixing surfaceon the first foam. The method further includes loading a deployableairbag onto the non-mixing surface. The method further includesinjecting a second foam into the second mold cavity and onto thenon-mixing surface adjacent the deployable airbag sufficiently to fillthe second mold cavity, and storing the second foam in the second moldcavity for a predetermined time sufficient to bond the first foam to thesecond foam along the non-mixing surface, whereby to define the multiplefoam substrate having the predetermined shape.

[0012] Yet another object of the present invention provides for amultiple foam substrate of a predetermined shape for impact energyabsorption manufactured by the process of injecting a first foam into afirst mold cavity of a mold sufficiently to fill the first mold cavity,storing the first foam in the first mold cavity for a predetermined timesufficient to form a substantially non-mixing surface on the first foam,injecting a second foam into a second mold cavity of the mold and ontothe non-mixing surface on the first foam sufficiently to fill the secondmold cavity, and storing the second foam in the second mold cavity for apredetermined time sufficient to bond the first foam to the second foamalong the non-mixing surface.

[0013] Yet another object of the present invention is to provide for amold for manufacturing a multiple foam substrate of predetermined shape.The mold comprises an upper portion and a lower portion. The upperportion has a first surface from which a first section extends and asecond surface from which a second section extends. The second surfaceis adjacent the first surface. The lower portion has a lower surfacefrom which a lower section extends. The first section is configured toengage with the lower section to define a first mold cavity at a firstclosed position. The second section is configured to engage with thelower section to define a second mold cavity at a second position.

BRIEF DESCRIPTION OF DRAWINGS

[0014]FIG. 1 is a perspective view of a mold drawn partially in phantomwhich may be used in carrying out the present invention;

[0015]FIG. 2 is a cross-sectional view of the mold of FIG. 1 to depict afirst foam injected in a first mold cavity of the mold;

[0016]FIG. 3 is a cross-sectional view of the mold to depict a secondfoam injected into a second mold cavity of the mold;

[0017]FIG. 4 is a flow chart of one method implemented in making amultiple foam substrate with the mold of FIG. 1 in accordance with thepresent invention;

[0018]FIG. 5 is a cross-sectional view of a multifoam substrate made bythe method of FIG. 4;

[0019]FIG. 6 is a cross-sectional view of another multiple foamsubstrate formed with an airbag made by the method of FIG. 4; and

[0020]FIG. 7 is a cross-sectional view of yet another multiple foamsubstrate formed with a fastener by the method of FIG. 4.

BEST MODE FOR CARRYING OUT THE INVENTION

[0021]FIG. 1 illustrates a mold 10 drawn partially in phantom. Mold 10may be used for manufacturing a multiple foam interior trim substrate inaccordance with one embodiment of the present invention. As shown, mold10 includes lower portion 12 and upper portion 14 (drawn in phantom).

[0022]FIG. 2 illustrates a cross-sectional side view of mold 10 in afirst open position. As shown, upper portion 14 includes first surface16 from which first section 20 extends downwardly toward lower portion12. Upper portion 14 further includes second surface 18 from whichsecond section 22 extends. Second section 22 includes extension 24integrally extending from second section 22. Lower portion 12 includeslower surface 26 from which lower section 28 extends upwardly. From theopen position, first section 20 is lowered to a first closed positionand engages lower section 28 to define first mold cavity 32. Moreover,upper portion 14 includes first injection hole 36 formed thereon throughfirst surface 16 and first section 20. Hole 36 is in fluid communicationwith first mold cavity at the first closed position. First injectionhole 36 is formed to receive first nozzle 42 through which first foam 43is injected into first mold cavity 32.

[0023]FIG. 3 illustrates a cross-sectional side view of mold 10 in asecond open position. From the second open position, second section 22is lowered to a second closed position and engages lower section 28 todefine second mold cavity 34. Upper portion 14 further includes secondinjection hole 38 formed thereon through second surface 18 and secondsection 22. Hole 38 is in fluid communication with second mold cavity 34in the second closed position, as shown in FIG. 3. Second injection hole38 is formed to receive second nozzle 44 through which second foam 45 isinjected into second mold cavity 34, as shown in FIG. 3. As shown, upperportion 14 rotates approximately 90° such that second surface 18 facesdownwardly toward lower surface 26 in order for second section 22 toengage with lower section 28.

[0024] Mold 10 may include conventional controls, plumbing, andmold-actuating mechanisms to allow proper operation of lower portion 12and upper portion 14. For example, portions 12, 14 of mold 10 may bemounted on tie-rods. In this embodiment lower portion 12 is stationary,while upper portion 14 is movable to permit opening and closing ofportions 12 and 14. Moreover, upper portion 14 is configured to rotateproviding pivotal movement such that second section 22 faces downwardlyand may engage with lower section 28. Actuations of portions 12,14 maybe by hydraulic, air cylinder, or manual.

[0025] Preferably, first and second foams 43,45 are polyurethane foamshaving different properties. For example, first foam 43 is preferably ahigh density flexible urethane foam and second foam 45 is preferably arigid structural foam. High density urethane foam is defined as foamhaving a density of a range between 80-125 kg/m³. Structural foam isdefined as urethane foam having a density of a range between 40-150kg/m³. The foams may respectively be supplied through their respectivenozzles from separate conventional mixheads (not shown) which dispense amixture of preferably isocyanate and polyol systems into the mold in theclosed positions. Moreover, the isocyanate and polyol systems may bestored in separate tanks, and metered to the respective mixhead. It isto be noted that other foams may be used which would not fall beyond thescope or spirit of the present invention. It is to be noted that thematerial comprising the foam, e.g., polyurethane, may be recycledmaterial or virgin (non-recycled) material.

[0026]FIG. 4 illustrates one method 110 implemented to manufacture amultiple foam interior trim substrate with mold 10 of FIGS. 1-3. Asshown in box 112, the method includes providing first foam 43 and secondfoam 45 of differing physical properties. In this embodiment, first foam43 is a flexible polyurethane foam and second foam 45 is a rigidpolyurethane foam. A difference in the densities between foams 43, 45provides a difference in physical properties of the two foams. In thisembodiment, first foam 43 has a density less than the density of secondfoam 45. However, first foam 43 may have a greater density than secondfoam 45. In such embodiment, mold 10 of FIGS. 1-3 will have sectionsconfigured to form interior trim substrate 210.

[0027] In this embodiment, first foam 43 is injected into first moldcavity 32, as shown in box 114 of FIG. 4. First foam 43 is injected intofirst mold cavity 32 through hole 36 by first nozzle 42 at a temperaturebetween about 70° and 90° F. and at a high pressure of up to 3000 poundsper square inch gauge (psig). Within about 1-15 seconds, first moldcavity 32 is filled with first foam 43, and nozzle 42 is closed. Firstfoam 43 in first mold cavity 32 is stored for 2-3 minutes in order tocure to form a substantially non-mixing surface of a resulting part asshown in box 116. During the curing duration, the resulting partincreases in strength and stiffness enough to substantially preventmixing of fist and second foams 43, 45 when second foam 45 is injectedthereon, as described below.

[0028] After storing first foam 43 in first mold cavity 32, upperportion 14 of mold 10 disengages from stationary lower portion 12 bymoving upwardly. Upper portion 14 then rotates about 90° in order forsecond surface 18 to face downwardly toward lower section 28 of lowersurface 26. Upper portion 14 then moves downwardly to engage secondsection 22 with lower section 28. Through hole 38, second nozzle 44injects second foam 45 into second mold cavity 34 onto the non-mixingsurface of first foam 43, as shown in box 118. When second mold cavityis filled, within about 1-15 seconds, nozzle 44 closes at a temperaturebetween about 70° and 90° F. and at a high pressure of up to 3000 poundsper square inch gauge (psig). As shown in box 120, second foam 45 isstored in second mold cavity 34 for 2-3 minutes in order to cure andbond with the non-mixing surface of first foam 43 to define the multiplefoam substrate having the predetermined shape. The curing durationallows the substrate to build up enough strength and stiffness to bebonded with the non-mixing surface of the resulting part and to beremoved from the mold when sufficient curing is complete. After removalof the substrate, the substrate is post-cured for 1-2 days atapproximately 70° F. to enhance physical properties and part stability.

[0029] As shown in FIG. 5, interior trim substrate 210 includes highdensity urethane foam portion 212 and structural foam portion 214integral therewith to define inner surface 216 and outer surface 218. Inthis embodiment, high density urethane foam portion 212 may act as asoft aesthetic outer layer for a show surface of an A-pillar section ofa vehicle compartment. Structural foam portion 214 acts as an energyabsorbing layer for collision impacts.

[0030] Outer surface 218 acts as a decorative cover or self-skinningsurface having aesthetic features, eliminating the need of clothdisposed thereon. This may be accomplished by having portions 12, 14 ofmold 10 be in communication with one or a plurality of heating platens(not shown) in order to heat mold 10 during method 110 of the presentinvention. The heating platens may be heated to a temperature rangingbetween 120° F. and 200° F. in order to heat mold 10 to a temperaturebetween 120° F. and 150° F. When the mold 10 is heated, the foam incontact with lower section 28 is molded to the shape of either firstmold cavity 32 or second mold cavity 34. The molded foam takes on agrain texture and firm surface. As a result of heating mold 10, interiortrim substrate 210 has outer surface 218 with aesthetic features that donot require cloth or an outer layer to be placed thereon. If desired,additional cloth or outer layer may be attached thereto in order toprovide a more aesthetic look.

[0031] Alternatively, the decorative cover or outer layer may be placedin mold 10 prior to injecting foam in mold 10, eliminating the need ofattaching an outer layer after heating. In this embodiment, thedecorative cover may be applied by a cloth placed thereon, as mentionedabove, or by a color spray sprayed onto mold 10 prior to injecting foamin mold 10. Other ways of applying a decorative cover in the mold priorto injecting foam in the mold do not fall beyond the scope and spirit ofthis invention. Also, although FIG. 5 depicts inner surface 216 flankingsheet metal structure 220, it is to be noted that surface 216 may beconfigured adjacent only one side of structure 220, as desired.

[0032] As shown in FIG. 6, substrate 310 includes high density urethanefoam 312, structural foam 314 attached to foam 312, and deployableairbag 316 also attached to foam 312. This may be accomplished byloading deployable airbag 316 onto high density urethane foam 312 afterstoring first foam 43 in first mold cavity 32 and prior to injectingsecond foam 45 in second mold cavity 34. In this embodiment, secondsection 22 is be formed without extension 24 to allow space for airbag316 on foam 312. It is to be noted that airbag 316 may be loaded ontofoam 312 automatically, e.g., by robotics, or manually, e.g., by hand.As shown, high density urethane foam 312 also includes notch 318 formedbetween airbag 316 and structural foam 314 in order to accommodatedeployment of airbag 316. As airbag 316 deploys upon impact, notch 318provides a portion of high density urethane foam 312 adjacent airbag 316to flex away from sheet metal structure 320, allowing airbag 316 todeploy in the vehicle compartment.

[0033] As shown in FIG. 7, conventional fastener 413 or a plurality offasteners 413 may be disposed within the mold in order to be bonded tofoams 412, 414 to provide an interior trim substrate 410 having anintegral fastener that may be directly attached to structure 420 of thevehicle. This eliminates the need of adhesives used to glue thefasteners onto the substrate.

[0034] While embodiments of the invention have been illustrated anddescribed, it is not intended that these embodiments illustrate anddescribe all possible forms of the invention. Rather, the words used inthe specification are words of description rather than limitation, andit is understood that various changes may be made without departing fromthe spirit and scope of the invention.

What is claimed is:
 1. A method of manufacturing a multiple foamsubstrate of predetermined shape with a mold having first and secondmold cavities, the method comprising: injecting a first foam into thefirst mold cavity sufficiently to fill the first mold cavity; storingthe first foam in the first mold cavity for a predetermined timesufficient to form a substantially non-mixing surface on the first foam;injecting a second foam into the second mold cavity and onto thenon-mixing surface on the first foam sufficiently to fill the secondmold cavity; and storing the second foam in the second mold cavity for apredetermined time sufficient to bond the first foam to the second foamalong the non-mixing surface, whereby to define the multiple foamsubstrate having the predetermined shape.
 2. The method of claim 1wherein the first foam is injected in the mold at a first closedposition.
 3. The method of claim 2 wherein the second foam is injectedin the mold at a second closed position.
 4. The method of claim 1wherein the first foam is a high density polyurethane foam having adensity ranging between 80-125 kg/m³.
 5. The method of claim 1 whereinthe second foam is a polyurethane structural foam having a densityranging between 40-150 kg/m³.
 6. The method of claim 1 wherein the stepof injecting the first foam includes injecting the first foam at atemperature range of between 70 to 90 degrees Fahrenheit and a pressurerange of between 90 to 3000 pounds per square inch gauge, and for a timeperiod of 1 to 15 seconds
 7. The method of claim 1 wherein thepredetermined time for storing the first foam ranges between 2.0 and 3.0minutes.
 8. The method of claim 1 wherein the step of injecting thesecond foam includes injecting the second foam at a temperature range ofbetween 70 to 90 degrees Fahrenheit and a pressure range of between 90to 3000 pounds per square inch gauge, and for a time period of 1-15seconds.
 9. The method of claim 1 wherein the predetermined time forstoring the second foam ranges between 2.0 and 3.0 minutes.
 10. Themethod of claim 1 further comprising: removing the substrate from themold; and curing the substrate at about 70 degrees Fahrenheit forapproximately 1 to 2 days.
 11. The method of claim 1 further comprising:loading a deployable airbag onto the non-mixing surface prior to thestep of injecting the second foam.
 12. The method of claim 10 whereinthe non-mixing surface has a notch formed thereon to allow for airbagdeployment.
 13. The method of claim 1 further comprising heating themold to a temperature between about 100 and 150 degrees Fahrenheit todefine the substrate having a firm outer surface.
 14. The method ofclaim 1 further comprising loading a substrate component in the moldprior to injecting the first foam in the first cavity.
 15. The method ofclaim 14 wherein the component is a fastener.
 16. A method ofmanufacturing a multiple foam substrate of a predetermined shape forselective impact energy absorption, structural differences, and airbagdeployment with a mold having first and second cavities, the methodcomprising: injecting a first foam into the first mold cavitysufficiently to fill the first mold cavity; storing the first foam inthe first mold cavity for a predetermined time sufficient to form asubstantially non-mixing surface on the first foam; loading a deployableairbag onto the non-mixing surface; injecting a second foam into thesecond mold cavity and onto the non-mixing surface adjacent thedeployable airbag sufficiently to fill the second mold cavity; andstoring the second foam in the second mold cavity for a predeterminedtime sufficient to bond the first foam to the second foam along thenon-mixing surface, whereby to define the multiple foam substrate havingthe predetermined shape.
 17. The method of claim 16 wherein the firstfoam is injected in the mold at a first closed position.
 18. The methodof claim 17 wherein the second foam is injected in the mold at a secondclosed position.
 19. The method of claim 16 wherein the first foam is ahigh density urethane foam having a density ranging between 80-125kg/m³.
 20. The method of claim 16 wherein the second foam is apolyurethane structural foam having a density ranging between 40-150kg/m³.
 21. The method of claim 16 wherein the step of injecting thefirst foam includes injecting the first foam at a temperature range ofbetween 70 to 100 degrees Fahrenheit and a pressure range of between 90to 3000 pounds per square inch gauge, and for a time period of 1 to 15seconds.
 22. The method of claim 16 wherein the predetermined time forstoring the first foam ranges between 2.0 and 3.0 minutes.
 23. Themethod of claim 17 wherein the step of injecting the second foamincludes injecting the second foam at a temperature range of between 70to 90 degrees Fahrenheit and a pressure range of between 90 to 3000pounds per square inch gauge, and for a time period of 1-15 seconds. 24.The method of claim 16 wherein the predetermined time for storing thesecond foam ranges between 2.0 and 3.0 minutes.
 25. The method of claim16 further comprising: removing the substrate from the mold; and curingthe substrate at about 70 degrees Fahrenheit for approximately 1 to 2days.
 26. The method of claim 16 wherein the non-mixing surface has anotch formed thereon to allow for airbag deployment.
 27. The method ofclaim 16 further comprising heating the mold to a temperature betweenabout 120 and 150 degrees Fahrenheit to define the substrate having afirm outer surface.
 28. The method of claim 16 further comprisingloading a substrate component in the mold prior to injecting the firstfoam in the first cavity.
 29. The method of claim 28 wherein thecomponent is a fastener.
 30. A multiple foam substrate of apredetermined shape for impact energy absorption manufactured by theprocess of injecting a first foam into a first mold cavity of a moldsufficiently to fill the first mold cavity, storing the first foam inthe first mold cavity for a predetermined time sufficient to form asubstantially non-mixing surface on the first foam, injecting a secondfoam into a second mold cavity of the mold and onto the non-mixingsurface on the first foam sufficiently to fill the second mold cavity,and storing the second foam in the second mold cavity for apredetermined time sufficient to bond the first foam to the second foamalong the non-mixing surface.
 31. A mold for manufacturing a multiplefoam substrate of predetermined shape, the mold comprising: an upperportion having a first surface from which a first section extends and asecond surface from which a second section extends, the second surfacebeing adjacent the first surface; and a lower portion having a lowersurface from which a lower section extends; the first section configuredto engage with the lower section to define a first mold cavity at afirst closed position, the second section configured to engage with thelower section to define a second mold cavity at a second closedposition.
 32. The mold of claim 31 wherein the upper portion isconfigured to engage with the lower portion by rotational andelevational movement of the upper portion.
 33. The mold of claim 31wherein the upper surface further includes: a first injection holeformed thereon, the first injection hole being in fluid communicationwith the first mold cavity at the first closed position; and a secondinjection hole formed thereon, the second injection hole being in fluidcommunication with the second mold cavity at the second closed position.